Year | Value | 2022 | 49.942851629968 | 2021 | 49.940556625769 | 2020 | 49.938006100831 | 2019 | 49.935134209448 | 2018 | 49.927532529495 | 2017 | 49.918416366422 | 2016 | 49.910658237102 | 2015 | 49.899691690167 | 2014 | 49.887347692888 | 2013 | 49.876782960299 | 2012 | 49.862844313391 | 2011 | 49.846080551178 | 2010 | 49.828386681581 | 2009 | 49.805413379122 | 2008 | 49.778120218055 | 2007 | 49.749376252582 | 2006 | 49.716297308148 | 2005 | 49.679280796136 | 2004 | 49.639995574387 | 2003 | 49.598981269051 | 2002 | 49.559612603185 | 2001 | 49.52086613169 | 2000 | 49.473138419224 | 1999 | 49.427528931842 | 1998 | 49.403438552673 | 1997 | 49.443433249729 | 1996 | 49.469093000591 | 1995 | 49.42356969984 | 1994 | 49.375960018282 | 1993 | 49.327260223702 | 1992 | 49.27880591426 | 1991 | 49.236975954825 | 1990 | 49.203897821571 | 1989 | 49.177445274768 | 1988 | 49.157693304505 | 1987 | 49.144085817128 | 1986 | 49.135073649454 | 1985 | 49.127853560269 | 1984 | 49.120839430116 | 1983 | 49.120706447367 | 1982 | 49.126401811225 | 1981 | 49.131480748875 | 1980 | 49.138010207429 | 1979 | 49.14568581683 | 1978 | 49.154336034597 | 1977 | 49.165416799273 | 1976 | 49.178824775522 | 1975 | 49.193044644863 | 1974 | 49.197926949655 | 1973 | 49.193606815359 | 1972 | 49.189307831417 | 1971 | 49.185194134814 | 1970 | 49.181990695703 | 1969 | 49.180238386249 | 1968 | 49.180096191106 | 1967 | 49.179543022361 | 1966 | 49.179867258775 | 1965 | 49.182631943363 | 1964 | 49.186515185192 | 1963 | 49.192105723788 | 1962 | 49.199890681693 | 1961 | 49.20931743692 | 1960 | 49.220369937094 |
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